The Tank Mine Clearing Blade: Eagle or Albatross?

by Captain John T. Ryan, Captain P. Kevin Dixon, and Sergeant First Class James L. Richardson "Red 1, this is Black 6. Send the plow tank forward." 2LT Bill Hardy sent his wingman forward to clear a path through the enemy minefield. This was the crew's first actual use of a plow and their ability to employ it properly concerned him. The platoon rehearsed breaching in the assembly area but did not drop the plow in fear that it might break and be unavailable for the mission. Aloud explosion interrupted 2LT Hardy's thoughts. "Red 2, this is Red 1. SlTREP over. "Red 1, this is Red 2. We didn't have enough spoil in front of the 26 blade when we hit the first mine and it blew up and broke our track. " "Send the back-up tank. " "Red 1, this is Red 2. We can't. The plow on the back-up tank dropped accidentally just after LD and broke - they're not back up yet." Great, thought 2LT Hardy. The other plow is stiJl in the UMCP on the 13 tank; bow am I going to explain this to the CO? The purpose of this article is to provide units a primer on the tank mine clearing blade that outlines the doctrine, tactics, techniques, and procedures for employment and addresses some of the most common problems seen at the National Training Center (NTC).

Scenes similar to 2LT Hardy's occur far too frequently at the NTC. Despite the fact the tank mine clearing blade (plow) is a critical task force asset, units seldom use it to its full potential. Frequent mechanical failures, insufficient crew training, and improper tactical employment often make the blade an albatross for those units so equipped. More often than not, a lack of crew training directly causes the maintenance problems. In turn, the maintenance problems inhibit the unit's ability to train with the blade. It is a vicious circle that leads to most units' inability to mechanically breach obstacles. General According to FM 20-32, Mine/Countermine Operations, the mine clearing blade "...is used to extract and remove land mines from the minefield. It consists.of a blade arrangement with scarifying teeth to extract mines, a moldboard to cast mines aside, and leveling skids to control the depth of the blade." "The mine clearing blade lifts and pushes mines, which are surface-laid or buried up to 12 inches, to the side of a track. The blade creates a 58-inch cleared path in front of each track. The skid shoe for each blade exerts enough pressure to activate most single-pulse mines and effectively clears a section of the centerline by explosive detonation. This action may disable the blade. A dog bone and chain assembly between the blades defeats tilt-rod fused mines." FM 20-32 further states that the mine clearing blade will not defeat multiple impulse pressure fuses and that mines armed with antihandling devices, antidisturbance devices, or magnetic and seismic fuses may activate and disable the blade when lifted. So, while the mine clearing blade is an effective tool for clearing a lane through an obstacle, it is not "mine proof' and units must use caution when considering its use as the sole means of mechanical breaching. However, mines do not disable the mine clearing blades at the NTC, maintenance does. Mechanical Failure The old adage that "training is maintenance and maintenance is training" certainly applies to the mine clearing blade. During the course of a 14-day rotation, a typical BnffF has an average of two out of six tank mine clearing blades fully mission capable (FMC) for any given mission. This clearly has a serious impact on a unit's ability to train in counterrnine operations. Many commanders decide not to train or rehearse with the operational blades they do have. They feel that if it gets broken, chances are it will not get fixed anytime soon. Although the blade can successfully execute a mechanical breach when less than fully mission capable, blade crews are not as effective when the blade is not. The need to manually Emergency Release Cable Assemblies Dogbone and Chain Figure 1. Location and Description of Major Components raise and lower the blade, or the inability to plow effectively due to missing parts, significantly increases the chances that enemy fires or mines will prevent the crew from accomplishing their mission. The following are the most common blade maintenance failures we see at the NTC. These three problems comprise approximately two-thirds of all blade failures we see.

• Broken lifting straps. (See Figure

I) The nylon lifting straps that raise and lower the blade suffer much abuse and become cut and frayed by concertina wire or other sharp objects. Consequently, they break when under load. To prevent damage to the straps, some units bolt wire catchers, similar to those on the old Ml51 bumper, on the moldboard in front of the straps. The straps also break frequently when the crew attempts to lift the blade with spoil on it. (When crews do this, the straps bear the additional load of the spoil and they break.)

• Inoperative electric lifting motor. The most common problem units experience with the motors is that the brushes bum out or one of several electrical relays malfunctions. Unfortunately, the only authorized repair for burnt-out brushes is to have a DS level mechanic replace the entire motor. To complicate matters further, the German-made motors often take several months to come in, once ordered. The contract mechanics at the NTC file the brushes from an old M I or M2I3 starter and use them in the lifting motor. This reduces blade down time from several months to only three to four hours. The electrical relays, on the other hand, are not particularly hard to acquire through normal supply channels, but most tank units do not keep them on hand. In a pinch, check with a sister mech battalion for the part. The relays (see Figure 2 for NSN) are identical to those found in the M2I3 electrical system.

• Sheared travel lock spindle and brackets. The travel lock spindle usually shears when the blade drops or hits something while the vehicle is moving at high speeds. When the spindle shears off, the downward motion of the blade causes the remainder 27

WI 401()'{)1-278-1216 251 ().{)1-276-7138 401 ()'{)1-277-5653 4020-01-289-8249 5945-01-277-0085 5945-01-277-0087 5945-00-500-7195 5945-00-686-6877 6105-01-277-0295 5315-01-277-5641 3040-01-K44-2243 5315-01-277-5643 3120-01-277-5652 Cable, Emergency R$ase Push beam, l. H. ea ea ea 2 1 2 6 prehensive training and licensing program for tank. crews. This would ensure that crews meet the standard prior to operating the blade on the battlefield. Other factors include units' apprehension about using the blade in training. Preventive Chain Assy. Strap, Ufting Solenoid Solenoid Umit Switch Relay Relay Motor, 3 HP Pin, Attaching Unk Spindle Travel Lock Roiler ea ea ea ea ea ea ea ea ea ea 2 2 2 4 4 Figure 2. Recommended PLL listing of the spindle to bend or break the bracket in which it is mounted (See Figure 3). For some reason, the spindles on the left travel lock break considerably more often than the right and in every case the bracket breili through the bolt holes. The only way t? fix the bracket is to replace the entIre push beam. This is a very time consuming operation that the crewmen can avoid if they use caution when driving with the blade. Once the blades break, units seldom get e parts to repair them during the ronon. Most units maintain very little if any PLL for the blade since it is a kit and not a reportable item. Therefore, units are reluctant to add these additional lines to their already limited PLL listing. So, they must order e repair parts, which have an excep-nonally slow tum-around time. The items in Figure 2 are a sample PLL stockage listing for a battalion equipped with twelve blades. These items represent a twelve month part demand history at the National Trainin& Center. Keeping these parts on the urut PLL should allow for rapid blade repair on the battlefield. Crew-Level Training As indicated earlier, proper crew-level training can prevent the majority of the mechanical failures and mine related casualties. More importantly, proper blade training will lead to an increased probability of mission success through the ability to rapidly breach obstacles. However, many crews arrive at the NTC with little or no formal training or experience with the mine clearing blade. for fear of breaking i or because the unit has no operational blades to train with. Also, when they do train, most units habitually only train those crews whose tanks have blades. However due to vehicle maintenance or other tactical considerations, non-blade crews often must employ the blade in a battle and the results are disastrous. For these reasons, we recommend that units thoroughly train and license all tank. crews on the blade. Currently, there is no single source manual for all crew-level mine clearing blade doctrine, tactics, techniques, and procedures. The three main documents that contain most of the basics for crew-level tank plow maintenance and employment are: 1M 9-2590-509- 10, Operator's Manual for the Mine Clearing Blade; 1M 9-2590-509-23 & P, Unit and Direct Suppon Maintenance Manual; and FM 20-32, Mine/ Countermine Operations. Without reiterating all of the information included in these manuals the following is a collection of obrva tions and some recommended techniques and procedures for tank plow employment. Plan: Many leaders fail to consider the 7,560-pound blade kit's effect on the tank. when they develop their plans. While the blade has little effect on the 's overall speed, it greatly redus Its maneuverability in rough terraIn. Crews that try to traverse rough terrain at high speeds cause most of the mechanical failures by ramming the blade into rocks, wadis, etc. In efense of the crews, they are only trymg to keep up with the rest of the unit. Thoroughly analyze the terrain with regard to the plow when planning routes. Plan

• Analyze the Terrain

• Position Blade Crews on Right Hand Side of the Formation Also, drivers of blade tanks cannot see to the right side of their vehicle because the power cable enters the vehicle through the right periscope Some contributing factors to this include the lack of an Army-wide com-Sheared travel lock spindle and bracket. 28 opening. This makes it difficult for the driver to maintain formation without a lot of guidance from the TC. Try to position the plow tanks on the right side of the unit formation if possible. Preparation: Drivers often inadvertently leave the ON/OFF power switch on the control box in the "ON" position. Subsequently, they sit or step on the RAISEJLOWER switch and cause the lifting motor to engage while the plow is in travel lock. This quickly bums out the lifting motors and the relays. To prevent this, securely mount or stow the control box in the driver's compartment and disconnect the main harness from the slave receptacle until ready for actual use. Prepare

• Stow Emergency Lifting Kit and Tools Crews sometimes neglect to properly prepare the blade prior to an operation. This is the cause of many real life and simulated battle damage casualties and failures. To prevent this, at- tach the moldboards prior to plowing. The extensions push the spoil and mines clear of the lane so they do not roll back under the plow tank's tracks. Ensure that the travel lock hitch pins are in the travel lock until it is actually time to drop the plow. TItis prevents the travel lock from disengaging prematurely and dropping the blade. Also, adjust the plowing depth to an 8", 10", or 12" depth, based upon the expected soil type - the softer the soil, the greater the depth. (The blade will not work effectively in some types of soil - namely rocky or frozen ground.) In addition, secure the emergency release cable handle near the driver' s hatch with tape or a strap. Frequently, when the driver has to use the emergency release to lower the blade, the cable is out of his reach and he must climb out of the hatch to pull it. Apiece of "100 mph tape" will hold it in place by the driver's hatch. Finally, stow the manual lifting strap and the tools required to open the #1 skirt together in an easily accessible place. This enables the crew to rapidly secure them and raise the blade manually if necessary. Execution: When you receive the order to initiate plowing, seek cover, if possible, pull the travel lock hitch pins, attach the main electrical harness to the slave receptacle and move to the beginning of the lane. Do not move the tank at high speeds with the travel lock pins removed as the plow is likely to drop unexpectedly and damage the plow and injure the crew. At the beginning of the lane, orient the tank in the proper direction of travel prior to dropping the blades. The blade achieves the best plowing width during straight line plowing. Next, close all the the hatches and traverse the main gun tube to the side to prevent damage by mine detonation under the blade. Execute. Seek Cover

• Move to Lane

• Back Out of Spoil (2 Meters)

• Insert Travel Lock Hitch Pins One of the more common mistakes that crews make when employing the blade is that they drop too close to the minefield. Consequently, the plow does not reach proper plowing depth prior to striking the first mine. FM 20- 32, MinelCountermine Operations, states that the lane should begin 100 meters from the estimated leading edge of the minefield. The lane should also extend for another lOO meters beyond the estimated far edge of the minefield to ensure that it extends through the entire minefield. This allows for a tactical safety factor. Operationally, however, TM 9-2590- 509-10 states that the crew must lower both moldboards at least 32 feet (10 meters) prior to the beginning of the cleared lane to allow the moldboards to reach operating depth. So, in a deliberate breach situation, drop the plow 100 meters out from the minefield and begin plowing; if you make unexpected contact with a minefield, ensure that you begin plowing at least 10 meters from the first visible mine. You can lower the mine blade while the tank is moving up to 8 to 10 MPH (12.9 to 16.1 KPH). However, you should use caution when lowering the blade while moving as it can cause 29 damage to the blade and injure the crew. When operating laterally on a slope, always drop the uphill blade first. Although the blade will plow through concertina wire effectively, the wire will often cut the nylon lifting straps - avoid wire if possible. At the conclusion of plowing, back up the tank approximately two meters to clear the blade from the spoil prior to lifting. Otherwise, the additional weight of the spoil may break the lifting straps. Tactical Employment The individual skills required to operate the mine clearing blade are the foundation for proper tactical employment. Units equipped with blade assets should train multiple crews in the use of the plow. In addition, the plan-prepare-execute methodology is useful in preparing a unit to employ the mine clearing blade to its full potential. Unit commanders provide an environment where well trained crews can execute. Plan: Effective breaching operations begin in the planning phase. Task organization of the mine clearing blades is a critical first step. In order to become a reliable breaching asset, commanders should mass all tanks equipped with a mine blade. (FM 71- 123 p. 6-107). This is a tactical decision based on METT-T. While there are other methods, massing plow assets achieves more consistent results. The reason for this increased performance is easier command and control and the ability to rehearse as a team. Breach site selection is another planning phase task. Plows perform better on flat terrain. Terrain analysis will reveal more advantageous ground to plow on. A rapid increase or decrease in elevation affects the depth setting on a plow, making it harder to maintain the proper amount of spoil in front of the blade. The commander should visualize the breach site in his OPORD. Use terrain overlooking the site or a terrain model. Place emphasis on the critical actions that occur in the vicinity of the breach site. These critical actions include when and where to release the travel lock hitch pins and drop the blade, and where to begin 'Plowing. 30 Preparation: Rehearsals are critical in proper employment of the tank blade. A full-up rehearsal on similar terrain in the most effective way to prepare crews. If time does not permit a full-up rehearsal, crews should at least drop the blade and plow a few meters to ensure the depth setting is appropriate. Commanders should rehearse redundance when employing plows. Rehearsing the exact order the commander intends to employ the plows and their relation to the support force will increase the survivability of the crews. This, coupled with thorough precombat inspections of the blade, wiU limit surprises at the breach site. Execution: In order to successfully execute the breach, units have to protect the blade tanks because they are a critical asset in a task force. Commanders must take care to allow the blade crews to find a covered and concealed position to prepare for operations and then direct the crews to the beginning of the lane. Before directing crews to the beginning of the lane, the commander should ensure that the conditions have been set for blade employment. Setting the conditions includes suppressing enemy direct fire systems, obscuring enemy observation of the breach site, and securing the breach site. Overwatch forces must effectively suppress enemy direct fire systems prior to the commitment of the blade tanks as the enemy will target them immediately. Use of artillery-delivered smoke and smoke pots on the enemy side of the obstacle will further enhance the blade crews' survivability. Task Organization Breach Site Selection

According to FM 71-1 (p. 3-45), the correct sequence of asset employment at the proposed breach site is to: lead with a mine roller to identify the edge of the minefield, fire and detonate an M 173 projected demolition charge or MICLIC to destroy most of the mines in the lane, and proof the lane with a mine roller or a mine clearing blade. However, since most units do not have or use the mine roller, they must visually identify the edge of the minefield, then fire the MICLIC, and proof the lane with the mine clearing blade. Simply plowing through the minefield without flI'St firing the MICLIC is a high risk operation as the first few mines are likely to disable the blade and the crew. Conclusions In conclusion, the tank mine clearing blade is a valuable task force asset. which, when maintained and employed correctly, will significantly enhance a unit's ability to mechanically breach obstacles. Proper blade training and maintenance procedures will ensure that the unit has fully mission capable equipment and trained crews available when the mission requires it. If 2L T Hardy used the tactics, techniques and procedures listed above, he would have nothing but success to explain to his commander. Captain P. Kevin Dixon is currently an Armor ColTm trainer on the Mechanized Infantry TF Training Team at the National Training Center. He is a 1986 graduate of The Citadel. He seNed as a platoon leader, executive officer, and S3 Air with 2-37 AR in Vi/- seck, Germany. Following AOAC he commanded HHC and Delta Company, 2-35 Armor at Ft. Carson, Colo. Sergeant First Class James L. Richardson is a tank platoon combat trainer with the Mechanized Infantry TF Training Team at the National Training Center. He has seNed as a tank platoon sergeant and leader, scout platoon sergeant and leader, battalion and division operations sergeant, company first sergeant, and national guard advisor. Captain John T. Ryan is currently an Armor ColTm trainer on the Mechanized Infantry TF Training Team at the National Training Center. A 1986 DMG from Western Carolina University, he seNed as a tank platoon leader, scout platoon leader, and company executive officer with 3-66 AR at Ft. Hood, Texas. Following AOAC, he seNed as a S3 Air, HHC commander and tank company commander in 3-66 AR, in Gar/stedt, Germany.